Macrolide antibiotics play a therapeutically important role, particularly with the emergence of new pathogens. Structural differences are related to the size of the lactone ring and to the number and nature (neutral or basic) of the sugars. Macrolides are classified according to the size of the lactone ring (12, 14, 15 or 16 atoms). The macrolide antibiotic family (14-, 15- and 16-membered ring derivatives) shows a wide range of characteristics (antibacterial spectrum, side-effects and bioavailability). Among the commonly used macrolides are erythromycin and clarithromycin. 
The search for macrolides active against MLSB-resistant strains (MLSB=Macrolides-Lincosamides-type B Streptogramines) has become a major goal, together with retaining the overall profile of the macrolides in terms of stability, tolerance and pharmacokinetics.
The present invention provides a novel class of 11-C-substituted erythromycin derivatives which possess antibacterial activity.
In one aspect of the present invention there are provided novel erythromycin derivatives represented by the formulae as illustrated below: or their racemates, enantiomers, regioisomers, salts, esters or prodrugs thereof, wherein
A is independently selected from R1, —CH(RA1)(RA2);
Each B, C, and D is independently selected from deuterium, halogen, R1, OR1, S(O)nR1, —NR1C(O)R1, —NR1C(O)NR3R4, —NR1S(O)nR1, —C(O)NR3R4, and —NR3R4;
or B and C taken together are selected from —O—, —S—, —N(R1)—, a substituted or unsubstituted alicyclic group, or a substituted or unsubstituted heterocyclic group;
or C and D taken together with the carbon atom to which they are attached are selected CO, C═CHR1, C═NR1, C═NOR1, C═NO(CH2)mR1, C═NNHR1, C═NNHCOR1, C═NNHCONR3R4, C═NNHS(O)nR1, C═N—N═CHR1;
E is independently selected from R1;
Each R1 is independently selected from the group consisting of: hydrogen, acyl, silane, a substituted or unsubstituted, saturated or unsaturated aliphatic group, a substituted or unsubstituted, saturated or unsaturated alicyclic group, a substituted or unsubstituted aromatic group, a substituted or unsubstituted heteroaromatic group, or a substituted or unsubstituted heterocyclic group;
Each of R3 and R4 is independently selected from the group consisting of: hydrogen, acyl, a substituted or unsubstituted, saturated or unsaturated aliphatic group, a substituted or unsubstituted, saturated or unsaturated alicyclic group, a substituted or unsubstituted aromatic group, a substituted or unsubstituted heteroaromatic group, a substituted, or unsubstituted heterocyclic group; or can be taken together with the nitrogen atom to which they are attached to form a substituted or unsubstituted heterocyclic or heteroaromatic ring;
Each RA1 and RA2 are independently selected from hydrogen, deuterium, halogen, R1, OR1, S(O)nR1, —NR1C(O)R1, —NR1C(O)NR3R4, —NHS(O)nR1, —CONR3R4, and NR3R4;
or RA1 and RA2, taken together with the carbon atom to which they are attached, form a substituted or unsubstituted alicyclic, aromatic, heterocyclic or heteroaromatic ring;
or RA1 and RA2 taken together with the carbon atom to which they are attached are selected from C═O, C═CHR1, C═NR1, C═NOR1, C═NO(CH2)mR1, C═NNHR1, C═NNHCOR1, C═NNHCONR3R4, C═NNHS(O)nR1, C═N—N═CHR1;
M is selected from the group consisting of: R1, C(O)R1, S(O)nR1, or C(O)NR3R4;
L is selected from the group consisting of: hydrogen, a substituted or unsubstituted, saturated or unsaturated aliphatic group, a substituted or unsubstituted, saturated or unsaturated alicyclic group, a substituted or unsubstituted aromatic group, a substituted or unsubstituted heteroaromatic group, or a substituted or unsubstituted heterocyclic group;
X, Y, X′, and Y′ are independently selected from the group consisting of: deuterium, halogen, R1, OR1, S(O)nR1, —NR1C(O)R1, —NR1C(O)NR3R4, —NR1S(O)nR1, —C(O)NR3R4, and —NR3R4;
or X and Y, taken together with the carbon atom to which they are attached, are C═O;
or X and X′, taken together with the carbon atoms to which they are attached, are C═C;
one of U or V is hydrogen and the other is independently selected from the groupconsisting of: R1, OR1, OC(O)R1, OC(O)NR3R4, S(O)nR1, or 
or U and V, taken together with the carbon atom to which they are attached, are C═O;
one of J or G is hydrogen and the other is selected from: R1, OR1, or NR3R4;
or, J and G, taken together with the carbon atom to which they are attached, are selected from: C═O, C═NR1, C═NOR1, C═NO(CH2)mR1, C═NNHR1, C═NNHCOR1, C═NNHCONR1R2, C═NNHS(O)nR1, or C═N—N═CHR1;
W is NR3R4;
R2 is selected from hydrogen, alkyl or halogen;
Rp is selected from a hydrogen and a hydroxy protecting group;
m is an integer; and
n is 0, 1, or 2.
In another embodiment of the present invention there are disclosed pharmaceutical compositions comprising a therapeutically effective amount of any compound of the present invention in combination with a pharmaceutically acceptable carrier or excipient. In yet another embodiment of the invention are methods of treating antibacterial infections in a subject with said pharmaceutical compositions. Suitable carriers and methods of formulation are also disclosed.
In a further aspect of the present invention there are provided processes for the preparation of any erythromycin derivative of formulas I, II, III, or IV via any synthetic route delineated herein.